<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>1:写一个页面，倒计时9秒后跳转到baidu，
			同时页面上显示剩余的秒数。</title>
			<style>
				#bd{
					font-size: 56px;
					margin-top: 200px;
					margin-left: 380px;
				}
			</style>
			<script>
				var count=9;
				setInterval(function(){
						if(count==0){
							location.href="https://www.baidu.com"
						}
						document.getElementById("bd").innerHTML=count--+"秒后跳转百度...";
				},1000);
			</script>
	</head>
	<body>
		<div id="bd"></div>
	</body>
</html>
